Recently, bio-diesels have been competitively developed and produced worldwide, and have also been domestically manufactured and commercially used as an additive to petro-diesel.
During the production of bio-diesel, a large amount of glycerol, corresponding to about 10% of the amount of the produced bio-diesel, is generated. However, supply of glycerol is greater than demand therefor, which leads to a continuous decrease in its value. Thus, it is economically advantageous to convert glycerol into chlorohydrins such as dichloropropanol which is a higher-value added product than glycerol.
Meanwhile, chlorohydrins such as dichloropropanol are used as a raw material for preparing epichlorohydrin. Most chlorohydrins which are currently supplied to markets are manufactured from propylene. Particularly, a method of preparing chlorohydrins includes two steps: preparing allyl chloride by high temperature chlorination of propylene and forming the chlorohydrins by reacting the allyl chloride with a chlorination agent using an excess amount of industrial water. However, the method of preparing chlorohydrins using propylene has problems in terms of instability of propylene supply and demand caused by increased price of propylene, generation of a large amount of waste water and other wastes, excessive initial investment costs due to the two-step manufacturing process, and the resulting difficulty in newly constructing/modifying a manufacturing apparatus.
Accordingly, a single-stage process of directly preparing chlorohydrins by reacting a polyhydroxy aliphatic hydrocarbon such as glycerol, which is a by-product of bio-diesels, with a chlorination agent in the presence of a catalyst is more economical. Such a single-stage process using polyhydroxy aliphatic hydrocarbon such as glycerol as a raw material is advantageous in that costs of raw materials can be reduced by using inexpensive polyhydroxy aliphatic hydrocarbon, the amount of waste water and other wastes can be dramatically reduced since industrial water is not required for the process, and thus the process is environmentally friendly, and initial investment costs related to the process and environment can be reduced.
However, when the method of preparing a chlorohydrin is used, water is produced as a by-product and the produced water inhibits chlorination of polyhydroxy aliphatic hydrocarbon such as glycerol. Thus, as the reaction proceeds, the reaction rate gradually decreases, and the selectivity of chlorohydrins is reduced.